Why Mowing a Lawn When Wet Is (Usually) Bad

Water drops on grass

We’ve all been in this situation: That overgrown grass needs to be cut, but the summer showers keep coming. Conventional lawn care wisdom says mowing a lawn when wet is bad. But you might have to use a machete before those rains are finished!

You really don’t have to wait to mow a wet lawn, says Bill Kreuser, assistant professor and Extension Turfgrass Specialist at the University of Nebraska-Lincoln. “Most turfgrass professionals mow in the morning when the dew is very high. It is good practice, however, to keep the heavy mower off the grass is the ground is very wet. This can cause compaction issues and long-term turfgrass damage.”

Although you can mow wet grass when it is necessary, there are valid reasons why mowing wet grass isn’t ideal:

Bill Kreuser, University of Nebraska-Lincoln
Assistant Professor Bill Kreuser, University of Nebraska-Lincoln

The Mower

  • It might take more juice to cut the grass, Kreuser explains. “It can put more stress on the mower because it will take more power, but mower engines are pretty simple and usually not too impacted if it occurs occasionally during a season.”
  • Cutting wet grass can dull the blade more quickly. Clean blades thoroughly before and after mowing a lawn when wet to keep the cut as sharp as possible. Stop and turn off the mower to check your blades as you go along, to clear any clogs that may form on the underside or at the side discharge. Maintain your machine and sharpen mower blades regularly to deliver a clean, healthy cut.

The Grass

  • Wet grass blades are heavy and sag to the ground. The mower blade often passes over those blades of grass instead of cutting them. So when your finished lawn starts to dry, the blades begin to stand upright, and your lawn shows uneven and unmown spots.
  • Diminished health. When you cut grass that is damp, the mower could leave ragged edges that can welcome fungal infestations, mold, and other problems. Wet soil allows roots to be ripped away, leaving bare patches. Only mow wet when it is necessary.
  • You could leave ruts and low spots. “Wait until the soil is dry enough to support the weight of the mower,” says Kreuser. The weight of a riding lawn mower could create low spots or ruts in the lawn. You end up with more work, filling ruts with topsoil and reseeding bare spots.
  • Clumping or clogging can occur. “If needed, raise the mowing height to remove less than one-third of the leaf at one time. I normally mulch mow (98% of the time) but if it is very tall, then you might need to bag,” Kreuser says. “This is the only time to ever bag clippings.”

The Homeowner

  • Keep it safe. Your personal safety is more important than a perfectly manicured lawn. You can easily slip and fall on wet turf or slopes and pull muscles or slip under the mower’s deck. Wear gripping footwear, long pants, and safety glasses while mowing. If you are using an electric mower, just wait until the next sunny day to mow. And definitely wait if a child is responsible for mowing the lawn – the risks of a child getting in a lawn mower accident are too great.
  • Be the weather watcher. Rain conditions such as lightning, streams or water or eroding soil can linger long after the rain stops. Pay attention to weather conditions and mow before the rain begins in your area. If you must mow after a long period of rain or if the soil is waterlogged, raise the mower deck to cut higher.
Rosie Wolf Williams

Rosie Wolf Williams

Rosie Wolf Williams has kept bees, grown vegetables and flowers for farmers markets, and never misses an opportunity to have a conversation with an interesting tree.